Vehicle closure anti-pinch assembly having a non-contact sensor

ABSTRACT

An anti-pitch assembly is used in combination with a closure device of a motor vehicle. The closure device includes a closure panel, i.e., a windowpane or door, and a motor for moving the closure panel between an open position and a closed position. In the closed position, the closure panel covers an aperture, i.e., a window or door opening, of the motor vehicle. The anti-pinch assembly includes a position sensor that is disposed adjacent the motor or the closure device. The position sensor generates a position signal indicative of the position of the closure panel. A capacitive sensor measures the capacitance of a field extending through the aperture. The capacitive sensor generates a signal therefrom. A controller is electrically connected to the position and capacitive sensors. The controller receives the position and capacitive signals and transmits a signal to the motor to prevent the motor from moving the closure panel toward the closed position when the output signals deviates from a series of predetermined values for more than a predetermined period of time.

This application claims the benefit of Provisional Application No.60/223,106, filed Aug. 3, 2000.

FIELD OF THE INVENTION

The invention relates to an anti-pinch assembly for a closure systemassociated with an aperture of a motor vehicle. More specifically, theinvention relates to an anti-pinch assembly for an aperture of a motorvehicle wherein the anti-pinch assembly includes a non-contact sensor.

DESCRIPTION OF THE RELATED ART

Motor vehicles typically have anti-pinch assemblies for closure devicesused to selectively open and close an aperture. By way of example only,an aperture of a motor vehicle is found within a door or side and theclosure device associated therewith is a window and its associatedcontrol mechanism. A non-exhaustive list of closure devices include doorwindows, sliding doors, lift-gates, deck-lids, sunroofs and the like.

The anti-pinch assemblies associated with these closure devicestypically sense the presence of a foreign object in the path of theclosure device by using characteristics such as motor current or afeedback device, such as a Hall effect sensor, tachometer and the like.These feedback devices sense an abnormal rate of change in the parameterbeing sensed relative to the normal or unobstructed operatingcharacteristic of the closure device. Simple detection of obstructionsbased on motor speed or electrical current passing through the motor areinadequate due to the normally varying characteristics of theseparameters through the full range of motion for the closure device.

U.S. Pat. No. 6,051,945, issued to Furukawa on Apr. 18, 2000, disclosurean anti-pinch assembly for a closure device. A CPU controls a motor thatmoves the windowpane between its open and closed positions. A Hallsensing device is positioned such that it can sense the velocity of theoutput shaft of the motor. To measure velocity, the Hall sensing deviceuses two Hall effect sensors that are disposed around the shaft of themotor. A magnet is secured to the shaft and provides the magnetic fieldrequired to operate the Hall effect sensors. Once the velocity of theshaft is measured, acceleration is derived and the force is calculatedusing the mass of the windowpane. This system requires the use ofmultiple sensors and calculations to correctly determine the presence ofan object.

SUMMARY OF THE INVENTION

An anti-pinch assembly is used in combination with a closure device of amotor vehicle. The closure device includes a closure panel and a motorfor moving the closure panel between an open position and a closedposition. In the closed position, the closure panel covers an apertureof the motor vehicle. The anti-pinch assembly includes a position sensorthat is disposed adjacent the motor of the closure device. The positionsensor generates a position signal indicative of the position of theclosure panel. A capacitive sensor is electrically connected to themotor and measures the capacitance through the aperture. The capacitivesensor detects a change in the fields through the aperture. A controlleris electrically connected to the position and capacitive sensors. Thecontroller receives the position and capacitive signals and transmits anobstacle signal to the motor to prevent the motor from moving theclosure panel toward the closed position when the capacitive signalsdeviate from a series of predetermined values for more than apredetermined period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the invention will be readily appreciated as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a schematic of one embodiment of the invention;

FIG. 2 is a side view of an aperture in a door of a motor vehicleincorporating one embodiment of the invention;

FIG. 3 is a graph of a reference map of data stored in a databaseutilized by one embodiment of the invention; and

FIG. 4 is a graph of measured data when an object is extending throughan aperture of the motor vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the FIGS. 1, an anti-pinch assembly is generally indicatedat 10. The anti-pinch assembly 10 is used in conjunction with a closuredevice. The closure device is comprised of a closure panel 12 and itsoperating system, discussed subsequently. The anti-pinch assembly 10prevents the closure panel 12 from pinching or crushing an obstructionor object (not shown) that may be extending through an aperture 14 of amotor vehicle 16 (both shown in FIG. 2). It should be appreciated bythose skilled in the art that the closure panel 12 may be any motorizedor automated structure that moves between an open position and a closedposition. By way of example, a non-exhaustive list of closure panels 12would include windowpanes, doors, liftgates, sunroofs and the like.Apertures would include window frames, door openings, sunroof openingsand the like.

The anti-pinch assembly 10 includes a control unit 18. The control unit18 is electrically connected, directly or indirectly, to a power source20. A conductor 22 graphically represents this connection. The powersource 20 is the power source 20 for the motor vehicle 16. The powersource 20 may be a battery, a generator or any other electricitygenerating device or combination thereof.

The control unit 18 is connected to a motor 24. The motor 24, receivingelectricity through a conductor 26 that, directly or indirectly, extendsbetween the power source 20 and the motor 24.

The motor 24 transforms the electrical energy into mechanical energy.More specifically, the electrical energy is transformed into a forcethat rotates a shaft 28 extending through the motor 24. The shaft 28 isoperatively connected to the closure panel 12. The operative connectiontransforms the rotational energy output of the motor 24 into an axial orpivotal movement of the closure panel 12, depending on the particulardesign of the closure panel 12.

The control unit 18 receives inputs from two sensors 30, 32. The firstsensor is a position sensor 30. The position sensor 30 identifies theposition of the shaft 28 of the motor 24. As the shaft 28 rotates, theposition sensor 30 identifies where along the rotation the shaft 28 isas well as how many rotations the shaft 28 has executed. The degree ofaccuracy is of the position sensor 30 is a variable that will depend onthe specific design.

The position sensor 30 is preferably a Hall effect sensor that utilizesa single magnet (not shown) that is secured to the shaft 28. The magnetrotates with the shaft 28 and its magnetic field affects the positionsensor 30 as it passes thereby.

Alternatively, the position sensor 30 may be a timer that provides anoutput signal indicative of the cycle time of the motor 24. Knowing thedirection of the motor 24 and the cycle time, the control unit 18 cantrack the position of the shaft 28 which then correlates shaft positionto closure panel position. A further alternative is a sensor mounted onthe glass run channel which provides a signal responsive to closurepanel position.

The second sensor is a non-contact sensor 32. The sensor 32 is definedas a non-contact sensor because an obstacle in the path of the closurepanel 12 can be detected prior to the object contacting either theclosure panel 12 or the frame defining the aperture 14. Morespecifically, the non-contact sensor 32 is a capacitive sensor 32. Thecapacitive sensor 32 is also disposed adjacent the motor 24. Thecapacitive sensor 32 detects changes in capacitance through the spacedefined by the aperture 14. The capacitance will not changesubstantially when the closure panel 12 moves therethrough due to designparameters. Changes occur prior to the immediate closing of the closurepanel 12 and when an object extends therethrough. An object extendingthrough the aperture 14 will disrupt the fields being measured by thecapacitive sensor 32.

Referring to FIG. 2, a door 36 of a motor vehicle 16 is shown. In thisembodiment, the door 36 is a standard side door that pivots about anaxis (not shown) to move the door 36 between its open and closedpositions.

The door 36 defines the aperture 14 (a window frame in this case) as anopening extending between a base 38 of the door 36 and around a windowframe 40 having a forward boundary 42, an upper boundary 44 and arearward boundary 46. The capacitive sensor 32 extends along the forward42 and upper 44 boundaries. The capacitive sensor 32 is designed tomeasure the field directly therebelow within the aperture 14.

A reference map is generated for the signal, in this example a voltage,from the capacitive sensor 32 as a function of position of the shaft 28.The closure panel 12 is moved from the open position to the closedposition. At each position interval, the signal from the capacitivesensor 32 and the position is recorded and saved in database 34.

FIG. 3 is a graphic representation of this reference map. The referencemap is a series of predetermined values 48 as function of closure panel12 position and stored in a database 34. As is represented in FIG. 1,the database 34 is a two dimensional array and forms a part of thecontrol unit 18. It should be appreciated by those skilled in the artthat the database 34 may be stored in a device separate and unique fromthe control unit 18.

The reference map represents the baseline for which the determination ofthe presence of a foreign object or obstacle will be made. If a signaloutput from the capacitive sensor 32 at a particular position issubstantially similar to that which is stored in the database 34, theanti-pinch assembly 10 will not alter the path of the closure panel 12.

Referring to FIG. 4, an example of data measured when an object existsin the path of the closure panel 12 is shown. The output signal ismeasured over a period of time and each output value is correlated witha position value. The correlated data is mapped in FIG. 4. With the datashown in FIG. 4, an object is detected at 50. The pinching of the objectbetween the closure panel 12 and either the forward boundary 42 or upperboundary 44 creates a change in signal value occurred prior to thedefined and expected increase as shown in the reference map of FIG. 3. Acomparator 45 measures the difference between the baseline value of FIG.3 and the actual measurement of the output signal. The increase inoutput signal defines a compare value that is the difference between themeasured signal and the signal value stored in the database 34 for thatparticular position in which the shaft 28 of the motor 24 is when thecompare value was created.

When the output value of the signal differs from the reference map ofFIG. 3 by a predetermined value for a specific period of time, an objectis determined to be extending through the aperture 14 and willeventually be pinched if the closure panel 12 continues to move towardits closed position. Contrast this from a data point 52 generated fromnoise in the anti-pinch assembly 10. The noise 52 does not last for anextended period of time, nor does it differ from the data 48 of FIG. 3by a compare value sufficient enough to be considered to be generated bya foreign object. The plateaus 54 in both FIG. 3 and FIG. 4 representthe end of travel for the closure panel 12.

When detection of an obstacle is made, an obstacle signal is generatedand the control unit 18 responsively overrides the motor 24 and eitherstops it from operating or reverses the direction in which the shaft 28is rotating. If the closure panel 12 is returned to its open position,the control unit 18 allows the motor 24 to operate according to normaloperation. If the closure panel 12 remains in the same position, theanti-pinch assembly 10 will not allow the closure panel 12 to continueto its closed position until after the compare value is eliminated.

The invention has been described in an illustrative manner. It is to beunderstood that the terminology, which has been used, is intended to bein the nature of words of description rather than of limitation.

Many modifications and variations of the invention are possible in lightof the above teachings. Therefore, within the scope of the appendedclaims, the invention may be practiced other than as specificallydescribed.

1. A method for preventing a closure panel from pinching an obstructionextending through an aperture of a motor vehicle having a motor to drivethe closure panel between an open position and a closed position, aposition sensor and a capacitive sensor, the method comprising the stepsof: measuring a capacitance of a field extending through the apertureusing the capacitive sensor as the motor drives the closure panelbetween the open and closed positions; generating a voltage signal fromthe capacitance sensor based on the capacitance measurements;identifying a position of the motor using the position sensor as themotor drives the closure panel between the open and closed positions;correlating the voltage measured to the position identified to createdata; comparing the data to a reference map to create a compare value;and detecting an object in a path of the closure panel as the closurepanel moves toward the closed position when the compare value exceeds apredetermined value; and measuring a time period that the compare valueexceeds the predetermined value to distinguish the detection of theobject from noise.
 2. A method as set forth in claim 1 including thestep of preventing the closure panel from continuing to move toward theclosed position when the object is detected.
 3. A method as set forth inclaim 2 including the step of preventing the closure panel fromcontinuing to move toward the closed position.
 4. A method as set forthin claim 3 including the step of retracting the closure panel to theopen position after the object has been detected.
 5. A method as setforth in claim 1 including a step of generating said reference map by:measuring a capacitance of a field extending through the aperture usingthe capacitive sensor as the motor drives the closure panel between theopen and closed positions in absence of an obstacle impeding travel ofsaid closure panel; generating a voltage signal from the capacitancesensor based on the capacitance measurements; identifying a position ofthe motor using the position sensor as the motor drives the closurepanel between the open and closed positions; correlating the voltagemeasured to the position identified; and storing said voltage andposition data.